This invention relates generally to liquid masking compositions which function as a paint for painting windows. The masking composition functions as a Differential Adhesion Compound (DAC) paint which sticks to the non-glass portions of the window and peels from the glass after the paint has dried, set or cured.
Differential Adhesion Compounds (DACs) for masking are known in the art, such as described in U.S. Pat. No. 5,618,582 issued on Apr. 8, 1997 and U.S. Pat. No. 6,319,548 issued on Nov. 20, 2001 to VanWinckel, both of which are incorporated by reference. DACs are used to prepare surfaces for painting when such surfaces are adjacent to other surfaces that need to be masked from the paint (e.g., masking window glass within a window frame prior to painting the window). The DAC adheres more strongly to the surface to be painted (e.g., wood or metal) and less strongly to masked surfaces such as glass. The DAC is applied over the surface to be masked along with at least some of the surface to be painted. After the paint is applied, the DAC can be easily removed from the masked glass surface while remaining in place over the painted frame surface.
VanWinckel discloses that a DAC paint can be made by adding 4% of by weight of glycerin to the total weight of the paint or preferable 10-20% by weight of glycerin to the weight of resin in the paint to an ordinary paint (column 8, lines 35-41).
Another DAC is disclosed in U.S. Pat. No. 5,866,199 issued on Feb. 2, 1999 to Swidler et al which is incorporated by reference. Swidler discloses a DAC paint with 1-10% pigment, most preferably 3-5% (column 7, lines 1-5).